An actor of dark-eyed intensity, Ron Silver won a Tony award for his scathing performance opposite Madonna as a sleazy Hollywood producer in David Mamet's Speed-the-Plow (1988). On screen, he memorably etched such characters as the lawyer Alan Dershowitz in Reversal of Fortune (1990) and a psychopathic killer stalking policewoman Jamie Lee Curtis in Blue Steel (1990). He was particularly effective when playing characters of uncertain loyalties, often manipulative or duplicitous. Personally, he achieved a lot of publicity as one of Hollywood's most active liberals – "I'm an actor by calling, but an activist by inclination," he said. In 1971 he became president of Actors' Equity. However, he caused a shock when, after 9/11, he became a supporter of George W Bush and switched his allegiance from Democrat to Republican.
The son of Jewish immigrants – his father was a clothing manufacturer and his mother a schoolteacher – he was born Ronald Zimelman in 1946 in New York City and educated at the University of Buffalo, where he received a bachelor's degree. Initially interested in Chinese studies, he obtained a master's degree in Chinese from St John's University and the College of Chinese Culture in Taiwan. After travelling to Vietnam, Cambodia, India, Japan and the Soviet Union on a work-study programme he returned to the US, where he worked as a teacher and social worker. He briefly considered working for the CIA, but then "sort of dwindled into acting".
Silver trained as an actor at the Herbert Berghof Studios and the Actors Studio and made his stage debut in Kaspar and Public Insult in 1971, the same year he had his first screen role, in The French Connection. In 1973 he starred in the hit off-Broadway farce El Grande de Coca Cola and in 1975 he went with the show to Los Angeles. The following year he made his television debut as the wimpish upstairs neighbour in the hit comedy series Rhoda. The programme's star, Valerie Harper, remembered him as "a big tease, with such irreverent humour". He stayed in Rhoda for two seasons, and other television shows included Hill Street Blues, Chicago Hope and The West Wing, in which he made 19 appearances as the president's advisor, Bruno Gianelli, receiving an Emmy nomination.
He had his first major screen role as a Bulgarian footballer in the comedy Semi-Tough (1977). Other films included Silent Rage (1982), Silkwood (1983) and the popular adventure tale Romancing the Stone (1984). In 1984, offered a role in the Broadway production of David Rabe's Hurlyburly, he returned to New York. ("I really liked LA," he said, "but I wasn't terribly successful out there." He had one of his most endearing roles as a man who tries to fulfil the dream of his dying mother (Anne Bancroft) to meet Greta Garbo in Garbo Talks (1984), which was filmed in New York by Sidney Lumet. In 1988 he and Joe Mantegna starred with Madonna in Speed-the-Plow, a play heavily publicised as Madonna's stage debut. The pop star did not come out of it well, surprisingly displaying little stage presence, but Silver and Mantegna were highly praised and Silver received both the Tony and Drama Desk Awards for what the New York Times critic Frank Rich described as "the performance of his career".
He returned to the screen with star billing as a nerdish womaniser in Enemies, A Love Story (1989). Madonna said: "Only Ron could play an incorrigible womaniser and still be endearing. In other words, he's dangerous."
Silver had one of his most effective roles as the psychopath in Blue Steel. "It was important to cast somebody who had not played a bad guy in a movie before," said the film's director, Kathryn Bigelow. "I found Ron to be all the character needed to be – someone who is very charming and who had a very complicated hidden agenda."
He received acclaim for his portrayal of Alan Dershowitz, Claus von Bulow's defence attorney, in the film based on the socialite Von Bulow's appeal against conviction for putting his wife into a coma, Reversal of Fortune, and he was a villain again in the futuristic thriller Timecop (1994).
Celebrated as one of Hollywood's most active liberals, a champion of human rights and a dedicated environmentalist and anti-nuclear campaigner, in 1989 Silver became acting president of the Creative Coalition, a group calling for artists to become involved in social issues. In 1990 he led stars including Susan Sarandon, Christopher Reeve and Alec Baldwin at a Washington rally against a ban on obscenity in federally funded arts projects – the event persuaded the first President Bush not to endorse the restrictions. In 1991 Silver succeeded Coleen Dewhurst as president of Actors' Equity.
His film career continued with Ali (2001), in which he played Muhammad Ali's corner-man, and When Billie Beat Bobby (2001), as tennis-player Bobby Riggs. His shock announcement after the 11 September 2001 attacks that he was supporting President George W Bush, citing Democratic policies on terrorism, alienated many. Silver suspected it cost him some roles.
"In this business," he said, "there are a million different reasons people don't want to work with you: You're too Jewish, you're not Jewish enough, they want a bigger star, they think you cost too much money. Most people are very economical with the truth out here, so it's very hard to determine cause and effect." His brother Mitchell said: "Ron's politics, as far as I know, were not shared by anyone he knew, except for the people he knew because of his politics. He told me that he did vote for Barack Obama in the end."
Ronald Zimelman (Ron Silver), actor: born: New York City 2 July 1946; married 1975 Lynne Miller (marriage dissolved, one son, one daughter); died: New York City 15 March 2009.